Reduce binary sizes for the kernel and userspace apps

kernel/Makefile

@@ -4,7 +4,8 @@ include $(ROOT)/mk/grabsrc.mk
 
 PUTCHAR_ ?= fb
 
-CFLAGS := -ffreestanding -Wall -Wextra -g -fcommon -nostdinc
+CFLAGS := -ffreestanding -Wall -Wextra -fcommon -nostdinc \
+					-fdata-sections -ffunction-sections
 
 CFLAGS += -I. \
           -I$(ROOT)/limine \
@@ -24,7 +25,8 @@ CFLAGS += -I. \
 
 include arch/$(ARCH)/$(ARCH).mk
 
-LDFLAGS += -nostdlib -static -T arch/$(ARCH)/link.ld $(shell $(CC) -print-libgcc-file-name)
+LDFLAGS += -nostdlib -static -T arch/$(ARCH)/link.ld $(shell $(CC) -print-libgcc-file-name) \
+					 --gc-sections --strip-all
 
 SRCFILES :=
 

mk/arch/toolchain-x86_64.mk

@@ -2,4 +2,4 @@ PREFIX := $(ROOT)/toolchain/root/bin
 
 CC := $(PREFIX)/x86_64-elf-gcc
 LD := $(PREFIX)/x86_64-elf-ld
-AR := $(PREFIX)/x86_64-elf-ar
+AR := $(PREFIX)/x86_64-elf-gcc-ar

mk/user/x86_64.mk

@@ -13,4 +13,8 @@ CFLAGS += -m64 \
 					-fno-strict-aliasing \
 					-O0 \
 					-mno-tls-direct-seg-refs \
-					# -fsanitize=undefined
+					-fdata-sections \
+					-ffunction-sections \
+
+LDFLAGS += --gc-sections \
+					 --strip-all

scripts/build-binutils-gdb.sh

@@ -7,6 +7,7 @@ cd build-bintuils-gdb
 ../binutils-gdb/configure --prefix="$PREFIX" \
                           --disable-nls \
                           --disable-werror \
+                          --enable-gold=yes \
                           --target=x86_64-elf
 make -j$(nproc)
 make install

scripts/build-gcc.sh

@@ -10,6 +10,7 @@ cd build-gcc
 ../gcc/configure --prefix="$PREFIX" \
                  --disable-nls \
                  --enable-languages=c \
+                 --enable-lto \
                  --target=x86_64-elf \
                  --disable-bootstrap \
                  --without-headers \

user/Makefile.inc

@@ -1,9 +1,10 @@
 CFLAGS := -ffreestanding -Wall -Wextra -g -fcommon -nostdinc \
-          -isystem $(ROOT)/std/include -isystem $(ROOT)/ulib -isystem $(ROOT)/share \
-          -isystem $(ROOT)/ulib/std
+	-isystem $(ROOT)/std/include -isystem $(ROOT)/ulib -isystem $(ROOT)/share \
+	-isystem $(ROOT)/ulib/std
 
 CURRENT_DIR := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
 
 include $(CURRENT_DIR)/arch/$(ARCH)/$(ARCH).mk
 
-LDFLAGS += -nostdlib -static $(shell $(CC) -print-libgcc-file-name) -T $(CURRENT_DIR)/arch/$(ARCH)/link.ld
+LDFLAGS += -nostdlib -static $(shell $(CC) -print-libgcc-file-name) \
+	-T $(CURRENT_DIR)/arch/$(ARCH)/link.ld

user/arch/x86_64/link.ld

@@ -25,4 +25,12 @@ SECTIONS {
     . = ALIGN(4K);
     _bss_end = .;
   }
+
+  /DISCARD/ : {
+    *(.eh_frame)
+    *(.eh_frame_hdr)
+    *(.gcc_except_table*)
+    *(.note*)
+    *(.comment)
+  }
 }